Formed zeolite bodies have been manufactured for use in various adsorption/desorption applications including drying of gases and liquids, separation of air into purified nitrogen and oxygen, and removal of CO2 from various gases.
In some applications where the controlled delivery of a small volume of gas is desired, zeolite adsorbent bodies having a desired gas adsorbed thereon have also been used as a source for delivery of gas. For example, in the instant carbonation of a beverage, zeolite adsorbent particles, typically CO2 preloaded 13X zeolite clay bound particles, have been used as a source of CO2 (see for e.g. U.S. Pat. Nos. 4,025,655 and; 4,147,808; and U.S. Patent Publications US 2011/0226343 A1 and US2013/0129870). In such applications, zeolite CO2 loaded particles are contacted with a displacement fluid, e.g. water, to release CO2. The liberated CO2 is then dissolved into a potable liquid to become a constituent of a carbonated beverage. In such applications, it is important for the adsorbents to have high gas adsorption capacity and gas desorption rates.
In addition to possessing the required adsorptive properties, adsorbent particles used as a gas source must also possess a sufficient attrition resistance to withstand the physical stresses associated with both transportation and use of the product in the desired application without undue particle breakage and dust formation. Gas loaded adsorbent particles may also be subjected to volumetric restraints due to limitations caused by packaging volume. This can adversely limit the amount of the desired gas available, thereby leading to a less efficient process and an undesirable product.
Further, in certain applications where a zeolite based adsorbent is used as a gas source, the adsorbent particles may be subjected to atypically harsh physical conditions, such as for example, in the instant carbonation of a beverage or in the delivery of medical gases, e.g. anesthesia gas, in single dose units (See U.S. Patent Pub. 2009/0071481). This is due to the physical wetting of the particles coupled with the rapid heating of the particles due to heat of adsorption effects and high gas pressures within the particles due to the very rapid desorption of gas. However, the acceptable level of particle breakage and attrition in these processes can be extremely low due to the extreme sensitivity of any contamination caused by dust or fines zeolite or binder particles in the final products of these process, e.g. contamination of the consumable beverage or of the inhalation gas. Prevention of the fouling of valves or other small orifices associated with apparati used in these processes is also critical.
Another volume constrained application where the delivery of a small amount of gas is desirable, include, for example, wine making procedures wherein the introduction of controlled amount of sulfur dioxide is released into must to reduce oxidation and inhibit the growth of wild yeast residing in the must application (See U.S. Pat. No. 4,345,511).
Accordingly, there is a need in various industries to provide improved adsorbent compositions and processes which are effective, efficient and productive to provide a gas source in volumetrically constrained applications.